/**
 * OSAmI: Open Source Ambient Intelligence
 * Copyright (C) 2010 Bull S.A.S.
 * Contact: osami-general@osami-commons.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 */

package org.osami.gateway.rules.heating.internal;

import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceEvent;
import org.osgi.framework.ServiceListener;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventAdmin;

/**
 * A {@code EventAdminProxy} is ...
 *
 * @author Guillaume Sauthier
 */
public class EventAdminProxy implements EventAdmin, ServiceListener {

    private BundleContext bundleContext;

    private EventAdmin proxied = null;

    public EventAdminProxy(BundleContext bundleContext) {
        this.bundleContext = bundleContext;
    }

    public void start() throws InvalidSyntaxException {
        bundleContext.addServiceListener(this, "(" + Constants.OBJECTCLASS + "=" + EventAdmin.class.getName() + ")");
    }

    public void stop() {
        bundleContext.removeServiceListener(this);
        proxied = null;
    }

    public synchronized void postEvent(Event event) {
        if (proxied != null) {
            proxied.postEvent(event);
        } // no-op
    }

    public synchronized void sendEvent(Event event) {
        if (proxied != null) {
            proxied.sendEvent(event);
        } // no-op
    }

    public void serviceChanged(ServiceEvent event) {
        switch (event.getType()) {
            case ServiceEvent.REGISTERED:
                Object service = bundleContext.getService(event.getServiceReference());
                if (service != null) {
                    proxied = (EventAdmin) service;
                }
                break;
            case ServiceEvent.UNREGISTERING:
                proxied = null;
                break;
        }
    }
}
